The critical thing is that you shoot in such a way that your character is "different" from the surroundings so that you can separate his image from the rest of the scene.

The classic "red dress" in Schindlers List is a useful example, because all that was required is that the scene had nothing else in the scene overlapping the dress that was the same color (it didn't even have to be necessarily red) but it DID need to be a color that could be isolated via mattes - so that the red pixels could be painted over a desaturated BG.

But replacing solid red cloth is one thing. Replacing or matting an entire character with not only clothing, but wardrobe differences, skin tones, flyaway hair, etc, is a whole mother ballgame.

One traditional process is to shoot the standard scene without the character, then use green screen to insert him into it. This provides the "difference" between one recording and another.

It's also possible to separate an existing character from the rest of a scene by electronically creating "traveling matte" which is isolating the character electronically so that you can control just the pixels of his image separate from the surrounding scene. This is more technically complex and time consuming.

You've probably seen web videos of how they animate hollywood characters by putting the actor in a key color full body suit that has "target balls" in strategic positions. The purpose is to create an outline of the actors movement that can be connected to a computer model to preserve the "moving through the scene" position information.

The bottom line is that there HAS to be something digitally "different" between the character and the scene for any of this to work.

Good luck.

Know someone who teaches video editing in elementary school, high school or college? Tell them to check out http://www.StartEditingNow.com - video editing curriculum complete with licensed practice content.

Is there no way of doing it with a much simpler method of fcp eg using the colour corrector tool? I know you can select a colour and desaturate the other colour I thought it could be possible to do the reverse of this

No. For this type of effect preparation and shooting correctly is the most important part, as Bill explained. Once that is done you can isolate the protagonist. Trying to isolate the portagonist without isolating it on set will simply not work, like shooting someone infront of a green screen wearing a green shirt.

Maisie, you could also check out the Mocha powered Slice X and Track X by CoreMelt for FCPX. its not as detailed as Mocha itself, but for many things could work very well, and is easy to use.

The only problem with rotoscoping would be isolating certain hair cuts. But it depends how perfect you really need it. If the protagonist has short hair or is wearing a hat, Mocha could be the perfect solution.

I've actually tried to use slice X to track a talking head so I could blur the background, but he was using his hands a bit and pretty quickly the tracker got lost.

Resolves tracker might actually pull it off as long as it stays pretty simple, and it's free.

But I think the point is it's cheaper and easier like Bill said, if you can put on the time during the shoot and plan on using more basic tools like green screen or the talent wearing very bizarre bright colors that don't exist elsewhere in the scene. You'd color adjust those colors in post of course.

[Bret Williams]"if you can put on the time during the shoot and plan on using more basic tools like green screen or the talent wearing very bizarre bright colors that don't exist elsewhere in the scene."

Exactly. Unless that's what you did, you're stuck with roto as your only possible option of singling the subject out from the background.

Bret, Ihad to use slice X to sharpen the subject and blur the background for one of the clips of a youtube fashion blog I'm shooting for a German Soap actress. One of the few times I've misfocused. She actually moves her arms alot. Slice X does get lost, but it still worked well, blurring the shape helps. Its not perfect but you do need to look closely to see imperfections. Her fans won't notice. When it goes online I'll post the link and see what people think.

But even Mocha needs some manual re-adjusting. I actually got a better result using the regular After FX tracker for a 4 point track a few months ago, and a Videocopilot fire under skin tutorial i was doing worked perfectly for one clip I used but got very lost on another clip. Of course, having limited Mocha experince.

Wasn't sure where he was going with that one either. But more on topic of Mocha, tracking and roto, anyone that hasn't seen the documentaries on the Gravity blu-Ray should take a look. It's really mind blowing the techniques they used.

I was attempting (lamely, to be sure) to help Maisie conceptualize the need to identify a complex objects spacial outline and position as it moves through a scene. Which is what, at the heart, she needs to do to get the effect she's describing.

Know someone who teaches video editing in elementary school, high school or college? Tell them to check out http://www.StartEditingNow.com - video editing curriculum complete with licensed practice content.

You might consider a compromise of sorts depending on your intent/concept.

You could easily switch to b/w in any POV shot on the protagonist or from the protagonist or any variation of this like CUs of the protagonists or certain scenes etc.

Don't know if it serves your needs but it would be really simple as opposed to really hard.

You could also dupe each clip, attach dupe as a connected clip to original and then crop/trim the section you want in B/W so that the combo above and below has his portion in B/W and the rest of the shot in color. This is not just him but the portion of the shot with him.

Or you could do this and have him dressed in b/w and just color correct the mid tones (skin tones) so that he appears colorless. That would leave most of the b.g. in color but he would appear b/w. You could have his hair dyed black or gray. You can also help this process with lighting and shooting him for a soft look with heavy contrast in the b.g.

This can be keyframed as well. The hard part will be perfect key framing within FC to follow his movement.

thanks everyone. I decided to use slice x and its looking good! however please could someone help me with key framing. Here is a video i found which is similar to the effect i want to create

so using slice x please could someone tell me how id fade from a colour to black and white? or black and white to colour? obviously as I'm using slice x its just a specific thing fading out like in this video, not the whole shot. thanks again

What they did in the video is something entirely different. And they clearly knew in advance what they were going for, how to to did and shot accordingly. They just used simple monochrome colors that are easy to pull a color matte from. So unless your subject is but one color, there's no comparison. But they will simply have cross-faded from the color matted version to the black and white version. No rocket science or key framing needed.